Sealing head for machines for heat treating threads

ABSTRACT

The present invention relates to a sealing head for machines for heat treating threads, comprising a frame ( 1 ) fixed to a pressurised chamber through which a conveyor belt passes, a pair of horizontal rollers ( 2  and  3 ) placed on top of each other and pressed against the opposite faces of the conveyor belt and of seals ( 4  and  5 ) to form a sealed closure between the rollers ( 2  and  3 ) and the frame ( 1 ), at least one ( 2 ) of the horizontal rollers ( 2  and  3 ) and the seals ( 4  and  5 ) being connected to the corresponding movement actuators ( 6  to  8 ).  
     Sealing head characterised in that the actuators ( 6  to  8 ) of the horizontal roller or rollers ( 2  and/or  3 ) and the seals ( 4  and  5 ) between the rollers ( 2  and  3 ) and the frame ( 1 ) are in the form of pneumatic actuators without pistons, namely of the balloon or bellows type.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.60/719,003, filed Sep. 21, 2005, which is incorporated by referenceherein in its entirety.

BACKGROUND OF THE INVENTION

The present relates to the field of the textile industry, particularlythe treatment of threads using heat treatment machines generally knownas heat setting machines, and relates to a sealing head for suchmachines.

These heat treatment machines comprise a pressurised chamber for heattreating textile threads laid on a conveyor belt traversing saidchamber, which is closed at both its ends by sealing heads eachcomprising a frame fixed to the pressurised chamber, a pair ofhorizontal rollers placed on top of each other and pressed against theopposite faces of the conveyor belt and seals to form a sealed closurebetween the rollers and the frame.

At present, the horizontal rollers are actuated by tightening means thatallow movement of at least one of the rollers in the direction of theother and the seals are in the form, on the one hand, of an upperelement and a lower element extended and resting against the generatorsof the two rollers and, on the other hand, of side sealing platesresting in a sliding manner against the corresponding ends of therollers.

The seals, both horizontal and vertical, are applied by means ofactuators, in the form of high-pressure hydraulic cylinders, withdrilled rods or cylinder blocks for the horizontal components andhigh-pressure hydraulic cylinders with angle return levers, for the sidesealing plates. The drilled cylinder blocks are, in fact, cylinders withseveral pistons and piston rods that are aligned in parallel in a singlecylinder block and have a single hydraulic supply, their operation beingin addition identical to that of the usual hydraulic cylinders.

These known actuators, in the form of cylinders, provide an adequateresponse to the problems posed, on the one hand, of application underpressure of the horizontal rollers against the conveyor belt and, on theother hand, of the seals against said rollers.

However, due to their structure in the form of high-pressure hydrauliccylinders, that is operating at a pressure of approximately 80 bar,there is a risk of hydraulic liquid leaks that could lead to said liquidflowing over the rollers and/or onto the textile material and, as acorollary, the contamination thereof. It is therefore necessary torecycle the oil. It follows that the hydraulic device for applyingpressure is subject to significant heating that could lead to a stoppageof the machine and the corresponding maintenance work.

In addition, because pressure is applied by means of hydraulic fluid,which cannot be compressed, the sealing head unit has a completely rigidsystem for applying pressure that allows no fluctuation or variation ofpressure on any of the actuators.

Finally, because of the actual structure of the present sealing headswith actuators in the form of hydraulic cylinders, the maintenance workis relatively complex and long and leads to correspondingly long machinestoppages, which reduces their productivity.

BRIEF SUMMARY OF THE INVENTION

The present invention aims to overcome these drawbacks by proposing asealing head for machines for the heat treatment of threads thatprovides easy access to the components subject to wear and avoids thedrawbacks relating to high-pressure hydraulic actuators.

Accordingly, the sealing head for machines for the heat treatment ofthreads, which comprises a frame fixed to a pressurised chamber throughwhich a conveyor belt passes, a pair of horizontal rollers placed on topof each other that are pressed against the opposite faces of theconveyor belt and of seals to form a sealed closure between the rollersand the frame, at least one of the horizontal rollers and the sealsbeing connected to the corresponding movement actuators, ischaracterised in that the actuators of the horizontal roller or rollersand the seals between the rollers and the frame are in the form ofactuators without pistons, namely of the balloon or bellows type.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood with the aid of the descriptionbelow which relates to a preferred embodiment given as a non-limitingexample, and explained with reference to the accompanying diagrammaticdrawings, in which:

FIG. 1 is an operating diagram of a sealing head according to theinvention;

FIG. 2 is a front elevation of a preferred embodiment of the invention;

FIG. 3 is a section along A-A of FIG. 2;

FIG. 4 is a section along B-B of FIG. 3, and

FIG. 5 is a part section, on a larger scale, along C-C of FIG. 2.

DETAILED DESCRIPTION OF THE DRAWINGS

FIGS. 1 to 4 of the accompanying drawings illustrate, by way of example,a sealing head for machines for heat treating threads, comprising aframe 1 fixed to a pressurised chamber (not shown) through which aconveyor (not shown) belt passes, a pair of horizontal rollers 2 and 3placed on top of each other which are pressed against the opposite facesof the conveyor belt and of seals 4 and 5 to form a sealed closurebetween the rollers 2 and 3 and the frame 1, at least one, 2, of thehorizontal rollers and seals 4 and 5 being connected to thecorresponding movement actuators 6 to 8.

According to the invention, and as shown more particularly indiagrammatic illustration in FIG. 1 of the accompanying drawings, theactuators 6 to 8 of the horizontal roller or rollers 2 and/or 3 and theseals 4 and 5 between the rollers 2 and 3 and the frame 1 are in theform of low-pressure actuators without a piston, namely of the balloonor bellows type. Preferably, these actuators 6 to 8 are actuators thatoperate under a maximum usage pressure of about 8 bar.

It should be stated that the illustration in FIG. 1 is diagrammatic andthe arrangement of the actuators 8 for the seals 5 is symbolic only, inorder to make the action of said actuators 8 perfectly clear, thepositioning of such an actuator being illustrated in FIG. 5.

The actuators 6, which are designed to apply at least one of the twohorizontal rollers on the conveyor belt against the other horizontalroller 3, are advantageously dual-action diaphragm cylinders and arearranged on the frame 1, on either side of said horizontal rollers 2 and3, and act on the driving and guiding shaft or shafts of said horizontalrollers 2 and 3, in the region of their ends, by means of slidingbearings 9 guided in the corresponding ends of the frame 1 andcooperating with the push rods 10, connected at one end to said slidingbearing 9 and connected by their other end to the correspondingdiaphragm of the actuator 6 (FIG. 4).

It is also possible to produce each actuator 6 in the form of twosingle-action actuators of the balloon or bellows type, these twoactuators each acting on either side, either of the bearing supportingthe shaft of the corresponding roller, or on a movement means connectedto said bearing.

Thus, it is possible to produce movement of at least one of thehorizontal rollers 2 and/or 3 of the sealing head to allow, for example,replacement of the conveyor belt, and thus a slackening of the belt,possibly while completely disconnecting the driving pinions 11 from saidhorizontal rollers 2 and 3, then tightening said rollers using apredetermined pressure and connecting the pinions 11 ensuring theirperfect functionality, even under maximum application pressure.

The seals 4 between the rollers 2 and 3 and the frame 1, which consist,for each roller 2 and 3 of a thin sealing sheet 12 mounted on a pivotingsupport 13 resting on the frame 1 by means of a longitudinal pivotingend stop 14, each co-operate with the corresponding actuator oractuators 7, in the form of balloons or bellows, by means of a loadtransfer rod 15, mounted on the frame 1 between the correspondingactuator 7 and the pivoting support 13 and loaded by a return spring 15′(FIG. 3). Thus, it is possible to apply the thin sealing sheet 12 on thecorresponding roller 2 or 3 under a load predetermined by the supplypressure of the actuators 7, cutting the supply of said actuators 7which has the effect of releasing the pressure on the pivoting support13 which can thus either release the thin sealing sheet 12 from thelower horizontal roller 3 under the effect of its own weight, or beraised to be placed out of contact with the upper horizontal roller 2 bymeans of an operating lever 13′ of said upper pivoting support 13.

The actuators 8 are advantageously balloon or bellows actuators and acton the seals 5 between the horizontal rollers 2 and 3 and the frame 1,which are in the form of sealing plates, by means of a force transferdevice in the form of an elbow lever 16 pivotally mounted about a pin16′ on the frame 1 and actuated so as to pivot by means of atransmission rod 17 comprising a return spring 17′. Thus, pressurisingthe bellows or balloon forming each actuator 8 has the effect of movingthe transmission rod 17 in the sense of a rocking action of the elbowlever 16 about its pin 16′, which leads to a corresponding transmissionof the load in the direction of the corresponding plate forming theseals 5 and the application under a predetermined pressure of said plateagainst the ends of the rollers 2 and 3. By providing an elbow lever 16,it is possible to produce a large increase in the application load ofthe seals 5 by adaptation of a torque transmission ratio correspondingto the ratio of the lever arms of the elbowed lever.

In fact, as shown in FIG. 5 of the accompanying drawings, the provisionof a lever arm which is longer between the pivot pin 16′ and the axis ofthe transmission rod 17 of one of the wings of the elbow lever 16 andanother which is shorter allows a mechanical increase in the loadapplied to the seals 5.

According to a characteristic of the invention, the actuators 6 to 8 areadvantageously pneumatic actuators. Due to the compressibility of theair or gas, the use of such pneumatic actuators allows the absorption ofvibrations and/or distortions. However, it is also possible to producethese actuators in the form of hydraulic oil or aqueous fluid actuators,as water or glycol.

In any event, these actuators, because of their structure with nosliding component outside their pressure chamber, are completely sealed,such that the risk of fluid leaks is eliminated. In addition, theiroperation at low pressure prevents any risk of overheating, which coulddamage their operation.

These actuators 6 to 8 are advantageously commercially available pliablebellows cylinders known under the name “Pneuride”, having dimensions of6″×1″ and available, in particular, under commercial references PM31061from NORGREN, 9109004 from PARKER or SP1536 from WEFORMA, andcommercially available pliable bellows cylinders known under the name“Pneuride”, having dimensions of 4.5″×1″ and available, in particular,under commercial references PM31041 from NORGREN, 9109400 from PARKER orSP2334 from WEFORMA, and also dual-action diaphragm cylinders available,in particular, under commercial references KHGS from CEF and COD600-50from REXROTH PARKER-BOSCH.

With pliable cylinders of this type, for a given cylinder height, theforce developed is proportional to the fluid pressure and, when thesealing head is clamped in the closed position, said cylinders act aspneumatic springs and the vibration insulation complies with the law:I=1−[1/(Fe/Fn)²−1]in which:

-   -   I=insulation rate    -   Fe=excitation frequency in hertz    -   Fn=natural frequency of the bellows in hertz

Depending on the conditions of use, the balloons forming the actuators 6to 8 may be made from natural or synthetic rubber of the butyl,epichlorine or nitrile type, these materials optionally being combinedwith a fabric insert.

If the fluid used is incompressible, the damping effect will be limitedto the deformability of the balloon, which is generally defined for amaximum use pressure of 8 bars and an operating temperature of between−40° C. and +130° C., depending on the material from which the balloonis made. It is also possible to add to this material anti-UV agentsintended to improve the ozone resistance or to provide specificprotection at the surface of the bellows.

The actuators 6 to 8 thus act simultaneously as actuators and aspneumatic springs and, while being compact in their construction,provide high power within a low overall size and also a high degree ofreliability and substantial operational flexibility. Furthermore, theseactuators do not require any maintenance, are resistant to aggressiveenvironments and have a very long service life.

In addition, as the flanges of these actuators are guided by a pin, thebellows are protected from harmful lateral vibrations, even in the eventof unsymmetrical wear to a sealing sheet or plate.

Moreover, since the diaphragms are, as is known, protected against theprojections of chemical agents by a stainless steel screen allowingoptimal control of the course of the bellows, this protection is alsoeffective against tearing, scratching, notching, particle projectionsand against shocks, as well as against accidental excess fluid pressure,the shield preventing dislodgment.

According to another characteristic of the invention, the differentactuators 6 to 8 are each provided with a drain valve and areadvantageously controlled automatically, either by means of aprogrammable controller, or by means of a pneumatic controller usingelements of pneumatic logic, standard logic or electropneumatic logicacting on the regulating valves arranged in the supply circuit of theactuators 6 to 8.

Preferably, the use of a heat treatment machine with sealing headsprovided with actuators 6 and 8 is effected according to a controlprocess that, from an open position of the treatment chamber, consistsof temporarily closing the horizontal sealing rollers 2 and 3 around theconveyor belt, then of aligning the horizontal sealing rollers 2 and 3by means of the seals 5, of next placing the horizontal sealing rollers2 and 3 under pressure against the conveyor belt, of then applying thethin sealing sheets 12 of the seals 4, under pressure, to the horizontalsealing rollers 2 and 3, of then applying the seals 5, under pressure,against the ends of the horizontal sealing rollers 2 and 3, of thenpressurising the treatment chamber, subject to authorisation to start updelivered by the contacts or sensors recording the closure of thedifferent drain valves and the opening of the regulating valvesallocated to the actuators 6 to 8, a fall in pressure in the chamber oran order to open a sealing head causing control of the regulating valvesto halt at the same time as the opening of the drain valve of thechamber and the issue of a signal prohibiting restarting, the controlactuators 8 of the seals 5, 7 controlling the thin sheets 12 forming theseals 4 and 6 for controlling the movement of one or both horizontalsealing rollers 2 and/or 3 being then successively depressurised inorder to return to the open position of the machine before a newtreatment cycle.

The temporary closure of the horizontal sealing rollers 2 and 3 roundthe conveyor belt is carried out simply by depressurising thedual-effect actuators 7, in such a way that the upper roller 2 fallsunder its own weight until it makes contact with the conveyor belt. Ifthe lower horizontal roller 3 is also mounted on sliding bearings,pressure should be applied to the corresponding actuators until theroller 3 makes contact with the conveyor belt.

Alignment of the horizontal sealing rollers 2 and 3 by means of theseals 5, after temporary closure of the horizontal sealing rollers 2 and3 round the conveyor belt, is carried out preferably by a series ofpressurisations and depressurisations of the actuators 8 acting on theseals 5. By such repetition of pressurisation and de-pressurisation ofthe actuators 8, the necessary slight relative movements of the rollers2 and 3 can be carried out in order to perfectly align their end face.

With the aid of the process described above, the provision of pressurereduction detection in the treatment machine allows any untimely openingof a sealing head following the emergency stoppage thus caused to beprevented and provides a perfectly controlled process for accessing theinterior of the chamber of the machine.

With the help of the invention, it is possible to produce sealing headsfor machines for heat treating threads that use actuators that can servesimultaneously to displace the various moveable components and to absorbthe vibrations caused during operation, it being possible for theseactuators to be supplied by different fluids, under low pressure.

In addition, simply because the sealing head is produced with suchactuators, it is possible to develop significant loads under low fluidpressure while taking up only a small space. In addition, since theactuators according to the invention are not provided with moveablemeans traversing them in the form of guided parts, they are not subjectto internal sealing problems and have a low production cost.

Moreover, these actuators are extremely robust, resist aggressiveenvironments and high temperatures, require no maintenance and canoperate with angular and axial misalignment.

Finally, due to their structure, the actuators 6 to 8 do not requirespecial guiding and can therefore be easily and rapidly mounted andremoved, reassembly being carried out without complex adjustment orspecial tooling.

Of course, the invention is not limited to the embodiment described andillustrated in the accompanying drawings. Modifications are possible,particularly from the point of view of the composition of the variouscomponents or by substitution of technical equivalents, without therebydeparting from the scope of protection of the invention.

1-12. (canceled)
 13. Sealing head for machines for heat treatingthreads, comprising a frame fixed to a pressurized chamber through whicha conveyor belt passes, a pair of horizontal rollers placed on top ofeach other and respectively pressed against opposite faces of theconveyor belt and of seals to form a sealed closure between the rollersand the frame, at least one of the horizontal rollers and the sealsbeing connected to corresponding movement actuators, wherein theactuators for the horizontal roller or rollers and for the seals betweenthe rollers and the frame are in the form of actuators without pistons,namely of the balloon or bellows type.
 14. Sealing head according toclaim 13, wherein the actuators operate under a maximum usage pressureof approximately 8 bar.
 15. Sealing head according to claim 13, whereinthe actuators that urge at least one of the two horizontal rollers onthe conveyor belt against the other horizontal roller are dual-actiondiaphragm cylinders and are arranged on the frame, on either side ofsaid horizontal rollers, and act on end regions of driving and guidingshaft or shafts of said horizontal rollers by means of sliding bearingsguided in corresponding ends of the frame and cooperating with push rodsconnected between said sliding bearings and the corresponding diaphragmsof the actuators.
 16. Sealing head according to claim 13, wherein eachactuator for the roller or rollers is in the form of two single-actionactuators of the balloon or bellows type, said two actuators each actingon either side, either of a bearing supporting a shaft of thecorresponding roller, or on a movement means connected to said bearing.17. Sealing head according to claim 13, wherein the seals between therollers and the frame, which consist for each roller of a thin sealingsheet mounted on a pivoting support resting on the frame by means of alongitudinal pivoting end stop, each cooperate with the correspondingactuator or actuators in the form of balloons or bellows by means of aload transfer rod mounted on the frame between the correspondingactuator and the pivoting support and loaded by a return spring. 18.Sealing head according to claim 13, wherein the actuators for the sealsbetween the horizontal rollers and the frame are balloon or bellowsactuators and act on the seals, which are in the form of sealing plates,by means of a force transfer device in the form of an elbow levermounted pivotally about a pin on the frame and actuated so as to pivotby means of a transmission rod comprising a return spring.
 19. Sealinghead according to claim 13, wherein the actuators are pneumaticactuators.
 20. Sealing head according to any claim 13, wherein theactuators are hydraulic oil or aqueous fluid actuators.
 21. Sealing headaccording to claim 13, wherein the actuators are each provided with adrain valve and are controlled automatically, either by means of aprogrammable controller, or by means of a pneumatic controller usingelements of pneumatic logic, standard logic or electropneumatic logicacting on regulating valves arranged in a supply circuit of theactuators.
 22. Control process for a heat treatment machine with sealingheads provided with actuators according to claim 13, wherein from anopen position of the treatment chamber, the process comprises steps oftemporarily closing the horizontal sealing rollers around the conveyorbelt, then of aligning the horizontal sealing rollers by means of theseals, of next placing the horizontal sealing rollers under pressureagainst the conveyor belt, of then applying thin sealing sheets of theseals, under pressure, to the horizontal sealing rollers, of thenapplying seals, under pressure, against ends of the horizontal sealingrollers, of then pressurizing the treatment chamber, subject toauthorization to start up delivered by contacts or sensors recording theclosure of drain valves and the opening of regulating valves allocatedto the actuators, a fall in pressure in the chamber or an order to opena sealing head causing control of the regulating valves to halt at thesame time as opening of the drain valve of the chamber and issue of asignal prohibiting restarting, the actuators for controlling the thinsheets and the actuators for controlling the movement of one or bothhorizontal sealing rollers being then successively depressurized inorder to return to the open position of the machine before a newtreatment cycle.
 23. Control process according to claim 22, wherein thetemporary closure of the horizontal sealing rollers round the conveyorbelt is carried out simply by depressurizing dual-effect actuators insuch a way that an upper one of the rollers falls under its own weightuntil said upper roller makes contact with the conveyor belt. 24.Control process according to claim 22, wherein alignment of thehorizontal sealing rollers by means of the seals, after temporaryclosure of the horizontal sealing rollers round the conveyor belt, iscarried out by a series of pressurizations and de-pressurizations of theactuators acting on the seals.